#!/usr/bin/python
# -*- coding:utf-8 -*-
# @author  : micah
# @time    :  
# @function: 
# @version :


"""
学生分数评级
"""

micah = 90

if 90 <= micah <= 150:
    print("等级S")
elif 80 <= micah <= 90:
    print("等级A")
elif 70 <= micah <= 79:
    print("等级B")
elif 60 <= micah <= 69:
    print("等级C")
elif 50 <= micah <= 59:
    print("等级D")
else:
    print("不合格")
